This study determines the effect of different commercial diluents on the quality of frozen Simmental semen. The extraction of fresh semen from 3 Simmental bulls using an artificial vaginal method was performed twice a week. Fresh semen with motility of >70% was further processed to frozen using a one-step dilution method, and the commercial diluents used were Andromed®, Optixcell®, and Steridyl®. The diluted semen was packed into mini-straws, equilibrated, frozen, and stored for further testing. Data were analyzed by analysis of variance (ANOVA), followed by Duncan Multiple Range Test (DMRT) analysis with a 5% confidence level. The results showed that commercial diluents significantly affected motility, viability, intact plasma membrane, abnormalities, and recovery rate of frozen semen (P<0.05). Commercial diluents with different sources of lecithin reported different results on the quality of frozen semen. Steridyl® has a more optimal ability to maintain the quality of frozen semen of Simmental cattle, followed by Optixcell® and Andromed®.